Green, ethical, energy issues in the news

GreatApe

pile-o-stone wrote: »

Hi Z,

I recall from earlier conversations that your house was quite ahead of its time when it was built and has a high level of insulation already. I can therefore understand that the cost of further upgrading your insulation levels to passive house standard would not be worth it. The savings on your already low heating bills would not cover the costs involved. It's the law of diminishing returns where adding more and more insulation becomes pointless.

For example, a house with 100mm of external insulation and high quality double glazing would not really benefit much from adding in a further 100mm and replacing the double with triple glazing. Ceratinly not enough for a reasonable payback. Certainly the occupants wouldn't feel much difference in comfort.

However, with a standard UK home that has little or no wall insulation and perhaps single or old double glazing, the cost of updating it to a similar level of insulation as your house would be cost effective. And as much of the cost of any building work is in labour, I'd suggest that doubling up and fitting fitting 200mm rather than 100mm of external insulation wouldn't double the cost. It'd just be the difference between 100mm of PIR insulation and 200mm, which isn't a huge amount.

Similarly, the total cost of fitting triple glazing instead of double glazing won't be double either. The labour costs for fitting would be virtually identical and any scaffolding would be exactly the same cost.

I'm not sure what point you were making about the multiple plasma TVs? If it was about how to heat the passive house, then this is predominantly passive solar gain (i.e. sun shining in through the windows) with a little heat from cooking food, bathing/showering and body heat. Heat recovery ventilation and attention to detail with air tightness (lots of tape!!) will help keep that heat in the house.

Replacing windows and installing solid wall insulation isn't cheap isn't quick and changes the character of a property. It's not going to happen on a large scale. Insulate to the point it is economic but we will as a country still need significant amounts of heat in the hundreds of TWh per year

And this is going to be a huge challenge that has no clear answer because the demand is so concentrated.
150-200 GW winter demand if you electrify hearting.

Converting one boiler to a heat pump is no big deal
Converting 35 million boilers to heat pumps and resistance heaters simply wouldn't be possible without mega mega infrastructure projects

pile-o-stone

zeupater wrote: »

Most of what I've read over the years seems to suggest an average of around £5k additional build cost per property would make the kind of difference to energy efficiency we'd need to get to, so if clearing the housing shortage needs ~350k new builds/year we're looking at an ongoing annual cost to purchasers of around £2billion ....

Just to add...

While we got sidetracked a bit in our posts where we were talking about retrofitting insulation to a house, the post above, which is the one I replied to, is actually discussing new builds.

My point about costs not doubling if you double the insulation thickness holds true for both retrofitting and newbuild. The difference with new build is that everything is zero rated VAT and the house is being built so insulation and labour costs are already in the mix, it's essentially just the additional cost of thicker insulation.

The trouble is that builders don't benefit from reduced heating bills and will just meet the existing building regs (if that, from the sloppy work I have seen on new properties), so it's in the hands of the government to implement more stringent standard for new builds and building control officers to inspect properties not just to make sure they're meeting planning restrictions but that they are also fitting insulation, windows and tapes correctly.

Having a final airtightness test that has a threshold the builder must meet before the house is signed off by building control would go some way to make sure the properties are built to a good standard.

Incidently, it's great to see so many councils adding insulation to houses externally - it's a quick fix that's relatively inexpensive and it's happening on a large scale.

Here is an example from Perth and Kinross, but there are numerous examples of councils and private individuals doing this work all over the UK:

https://www.scottishhousingnews.com/article/perth-kinross-council-embarks-on-1-3m-round-of-external-insulation-works

Not quite passive standards, but great to see all the same

GreatApe

We are now two years into the saga of ASHPs and on our third machine. The installer has gone out of business and things have got messy.
Our problem is that with all three machines whenever the outside temperature is in the range plus or minus 3 to 4 degrees C AND the Relative Humidity is above 85% the external heat exchanger turns into a block of ice and cannot dissipate the cold that it generates, hence no heat either. Of course this can only be demonstrated during the winter, for the first winter we were given various explanations and then in the 2nd we had the third and present system installed which we were assured worked down to -15. It may well do, if the Dew point is -20 or so. In our climate it doesn't and last winter we had a number of days with no heating and of course support is difficult to get when your supplier has gone down the tubes. HIES has tried hard but with only limited engineers support is poor to nonexistent.
In our view which we have repeatedly stated the system is not fit for purpose. The fact that various advisory sites now talk about auxillary heating during cold weather seems to say it all.

Hi there,
We've recently had an ashp installed and were promised the world before installation. The installation was a mess, took them far longer than they stated with repeat visits over a few weeks, only for the company to start telling us that the system might not be very effective with our radiators, and one engineer admitting he thought we'd been mis-sold the system. My question is, is there much can be done if you have? What would be the course of action? Many thanks for any help.

Hi

you have been miss sold any one who buys a ASHP has had them miss sold as they are abysmal, they use an astronomical amount of energy to produce very little heat. If you have been told they will supply your rsds or even heat your hot water this is a complete lie as it wont the energy output isn't high enough, even if you have one that's over sized the amount of electricity it uses will make it extremely expensive and cost you a hell of a lot more and increase your carbon foot print. I have done a lot of studies, calculations and assessments on a number of systems, I have witnessed these across the country and there really isn't a single positive that I can say about them. (Meng, Beng, Senior engineer. IMET)

Heat pumps work well but..
Air source heat pump won't work properly for temperatures lower than -2 outside. It's just not warm enough - not enough "heat" to warm up decompressed gas which circulates inside the pump. It will freeze the pump with low temperatures outside. So you need a backup heat source for coldest nights..
Maximum efficiency for heat pump will be when heating water up to 35degrees Celcius. So ideal for underfloor heating but not good for radiators.. Good in UK for places close to the sea as most of the nights are cool - so you need heating at night more often than not - and temperatures rarely fall below 0.
Hope it helps ..

Wojciech P.

This last one is particularly worrying because if you need resistance heaters for when it's really cold that means heat pumps won't reduce peak demands Vs resistance heaters at all....

I'm very dissatisfied with the efficiency of the air source heat pump. It is not what it was sold to be. It is really very expensive to run - much more than my previous boiler. I actually want it to be removed and to go back to my old system. Can anyone help? I signed up to the Government Scheme and I know have a debt because we took out a loan to pay for it. I understand that I was getting much of that loan back through the incentives. That is not the issue it is the actual cost of the heating which had quadrupled over the past three months and it is not sustainable. Any contact nos to start the process of getting rid of it would be appreciated.

zeupater

pile-o-stone wrote: »

Hi Z,

I recall from earlier conversations that your house was quite ahead of its time when it was built and has a high level of insulation already. I can therefore understand that the cost of further upgrading your insulation levels to passive house standard would not be worth it. The savings on your already low heating bills would not cover the costs involved. It's the law of diminishing returns where adding more and more insulation becomes pointless.

For example, a house with 100mm of external insulation and high quality double glazing would not really benefit much from adding in a further 100mm and replacing the double with triple glazing. Certainly not enough for a reasonable payback. Id wager the occupants wouldn't feel much difference in comfort.

However, with a standard UK home that has little or no wall insulation and perhaps single or old double glazing, the cost of updating it to a similar level of insulation as your house would be cost effective (as you already said in your earlier conversation).

I'd argue that doubling up and fitting fitting 200mm rather than 100mm of external insulation wouldn't double the cost. It'd just be the difference between 100mm of PIR insulation and 200mm, which isn't a huge amount and extra cost for longer mechanical fittings to attach the insulation to the wall.

Similarly, the total cost of fitting triple glazing instead of double glazing won't be double either. The labour costs for fitting would be virtually identical and any scaffolding would be exactly the same cost.

I'm not sure what point you were making about the multiple plasma TVs? If it was about how to heat the passive house, then this is predominantly passive solar gain (i.e. sun shining in through the windows) with a little heat from cooking food, bathing/showering and body heat. Heat recovery ventilation and attention to detail with air tightness (lots of tape!!) will help keep that heat in the house.

Hi

It's a one off architect design which included solar gain as a primary heating design concept (how's that for an early 80's build!) & you're right, it was insulated well for when it was built (early '80s) with CWI, DG, & 100mm loft insulation etc but the main benefit that most homes still don't benefit from is a really well insulated floor slab through incorporation of a decent pumice thermal layer plus twin thermal block construction in addition to CWI to the second floor, they've always made a considerable difference! ... the main single energy benefit we've achieved is from insulating the loft spaces as we have 3 totalling around 200sqm which have been topped up to ~500mm (or it's equivalent) in two separate phases over about 5 years (+200+200) ... it's effectively so cheap and has such a massive effect on energy consumption that I can't understand why the government don't just buy up the worlds (! ... ) supply of rolls, directly hire an army of installers with vans & just go door to door fitting it for free without resorting to convoluted application & entitlement processes! ...

Triple glazing is one of the (80:20) improvements that makes little sense for us considering the additional energy savings to cost ratio, so it still sits on the back burner ... having mentioned that, a considerable proportion of our heat provision is through solar gain, so we already benefit from a negative heat-loss on that front ...

On the multiple TVs & Passivhaus ... the point is that the idea behind passivhaus is to minimise direct heating requirements & rely on the passive heat from bodies, electrical equipment etc ... when the standards were set, typical fittings & goods were assessed and their combined heat output was classified as being resultant from primary energy consumption, therefore passive. the problem now is that LED lights have replaced halogen etc and LED TVs have replaced CRT & Plasma units, both formerly considerable heat sources ... effectively you could easily be in a position where inefficient primary energy consumption would be needed to create passive heat just to supplement a heat provision system which is now undersized if the latest technology for lighting & entertainment (&cooking!) were installed, just to conform with the certification process - for example, for myself & the TV & lights I have on in the room I'm sitting in now has the passive heat output of ~1.5adults whereas just a few years ago it would have been that of at least 5 ... if it gets chilly, I'd have the theoretical option of consuming part of the tight annual 15kWh/sqm allowance for direct heating, or find an additional Plasma TV (~3 adult passive heat equivalent!) to turn on & consume part of the (now underutilised!) 60kWh/sqm/year primary energy allowance! ... a pretty serious issue with relatively outdated Passivhaus requirements as they stand!

HTH
Z

Martyn1981

zeupater wrote: »

Heat pumps sitting alongside batteries make far more sense ... a 4kW.t ASHP setup running at ~60% capacity on a 24hr basis would probably suit the majority of UK home winter heat-load requirements where insulation is at reasonable levels without impacting on peak-load generation & that's the most likely & most cost effective pathway to follow ....

HTH
Z

Posting more for fun, and so all can laugh at me, but I pondered your suggestion above v's district heating.

It seems simple and sensible, so I extended it slightly by adding PV to add a small amount extra in the cold months, and to benefit from the batts in the sunny months.

Then I played further with it to include a large (but still small!) community wind turbine with its own large(ish) battery serving the local community to support HP's.

Then realised you don't need to be directly connected to the big battery if you balance export to the grid (from the batt/WT) with the imports to the associated houses in the scheme.

Then I realised you could do this simply through a leccy company running the WT/batt and your account.

Then realised, you can do all this by buying from a RE leccy supplier, or an account that ensures the company buys in RE leccy equivalent to what it sells to customers.

Then realised, all this exists already.

So HP plus renewable leccy supplier. So distributed heat option already exists, and to a small scale, I already take part with my PV and small ASHP.

Once again I re-invented the wheel, but at least I'm willing to laugh at myself and hopefully share a giggle or two with others.

GreatApe

Heat pumps seem not to work at the most critical times

When the temp is low 2-5 centigrade and the relative humidity is high they ice up

Hence while they may reduce overall demand relative to resistance heaters, they won't reduce peak demand as the backup resistance heaters would need to be used for heating when it's cold yet humid

As such to electrify UK heating you are probably looking at North of 200GW perhaps closer to 250GW grid. Since you can't do seasonal storage that means you will need thermal power stations to the tune of 200-250GW plus 10% spare capacity

How will the need to build 200 new big gas fired power stations sit with the green cheerleaders and importantly how much will this cost and add to bills? Not to mention having to more or less expanded transmission lines 3-4 fold

As I keep saying, electrifying heating with heat pumps sounds like a good idea and perhaps looking at one property it can be done today and things work. Try converting 35 million gas boilers and....well you're screwed pretty quickly

Even making useage illegal outside of peak times you'd only be able to add about 1-2 million units before the non peak times become the peak times. Plus the way heat pumps work you don't really want to make it illegal to use for 4 hours of the day running rads at 40 centigrade takes a very long time to heat things up heat pump systems really want to be running constantly

So I suggest once more
Trying to build 200 new gas fired power stations to make heat pumps work probably isn't a good idea
Better to build 100GW of heat reactors and distribute that heat

Some time around 2030 you will realise electrifying hearing on a large scale wasn't the best of ideas.
Convert 2.5 million boilers per year in the 2030s to heat pumps and you will need to build a large new gas fired power station every 2 months........ I doubt the grid can even expand that fast certainly new overhead power lines would be needed and those will be delayed and delayed thanks to NIMBYs

NigeWick

zeupater wrote: »

Most of what I've read over the years seems to suggest an average of around £5k additional build cost per property

I remembered seeing this - Smart’ carbon positive energy house https://buff.ly/2MBK8Uz - some time ago. There should hopefully be even more savings after four years?

pile-o-stone

NigeWick wrote: »

I remembered seeing this - Smart’ carbon positive energy house https://buff.ly/2MBK8Uz - some time ago. There should hopefully be even more savings after four years?

Thanks for posting that. I wonder how much the heatpump is used if the house is so well insulated and air tight? Perhaps it's used mostly for hot water demand more than space heating, though I would have thought it'd be cheaper to have immersion heaters, especially if connected to the PV?

zeupater

NigeWick wrote: »

I remembered seeing this - Smart’ carbon positive energy house https://buff.ly/2MBK8Uz - some time ago. There should hopefully be even more savings after four years?

Hi

Nice concept project, but I fear that the inclusion of 'best' & 'affordable' within the same sentence provides a pretty comprehensive oxymoron as a considerable level of compromise would be necessary to attempt both! ...

... for example, when we costed more efficient windows we looked at a couple of aluclad options ... they may be good in terms of efficiency, but they're certainly towards the lower end of the spectrum from a cost benefit viewpoint ....

Looks more like the architect lost the thread when considering materials & aesthetics vs budgetary issues .... doubt that one comes in anywhere near the £5k average on-cost to make a difference on new builds! ...

HTH
Z

Coastalwatch

Martyn1981 wrote: »

Posting more for fun, and so all can laugh at me, but I pondered your suggestion above v's district heating.
Then I played further with it to include a large (but still small!) community wind turbine with its own large(ish) battery serving the local community to support HP's

So HP plus renewable leccy supplier. So distributed heat option already exists, and to a small scale, I already take part with my PV and small ASHP.

Once again I re-invented the wheel, but at least I'm willing to laugh at myself and hopefully share a giggle or two with others.

Think I'm with you on that one Mart being in a similar such position. Now if only we could address the imbalance somewhat between what we might get paid for exporting and what we currently pay for importing then utopia shouldn't be too far away.

Just have to resolve the thorny issue of the unecessary standing daily charge by a small increase in the unit cost of energy to offset this. Not difficult is it?

In theory our system generates sufficient energy annually to cover all our domestic requirements plus around half those required for charging our EV. It's just the time shifting problem thats difficult to overcome.
I like your idea of a community Wind Turbine, perhaps we could club together to lease the output from one of the many visible off the coast here today.
If only life were that simple.:)